Forecasting of a boosted locomotive gas diesel engine parameters with one- and two-stage charging systems

Vladimir V Sinyavski,Vladislav V Kremnev,Pronchenko Grigori,Mikhail G Shatrov

doi:10.31181/rme200101192s

Vladimir V Sinyavski, Vladislav V Kremnev + Show 2 more

Open Access

https://doi.org/10.31181/rme200101192s

Copy DOI

Abstract

Conversion of locomotive engines for operation on natural gas lowers considerably expenses for fuel and reduces exhaust emissions which makes it possible to omit large and expensive aftertreatment systems. The permanent need to raise the engine power requires a considerable increase of the boost pressure. This can be realized by using a high pressure turbocharger or a two-stage charging system. In the research, parameters of a high boosted D200 6-cylinder locomotive engine having D/S=200/280 mm are forecasted using a one-zone model developed in MADI. An analysis was carried out to explain why the 1st stage compressor of the two-stage charging system should be specially profiled to have its map tilted to the right. Calculations were performed for the gas diesel engine having a break mean effective pressure (BMEP) 2.7 MPa with one and two-stage charging systems. In both cases, close fuel efficiency was obtained, though for the two-stage charging system, the boost air pressure was higher. The engine with one turbocharger had no reserves for further power augmentation while the two-stage charging system enabled to increase the boost air pressure further. Therefore, parameters of the engine having a higher BMEP 3.2 MPa were calculated. In that case, not to exceed the peak combustion pressure, a retarded fuel injection was used which resulted in fuel efficiency drop by approximately 1.5%.

Highlights

Conversion of diesel engines for operation on natural gas is important because there are more explored reserves of natural gas than oil on our planet, the price of natural gas is twice lower in Russia and the price difference will grow as the oil reserves are depleted
Parameters of joint operation of a gas diesel engine with one-stage and two-stage turbocharging systems were calculated by a model of diesel/gas diesel/gas engine developed in MADI (Khatchiyan et al, 2015)
The peak cylinder pressure pz exceeded the critical value of 22 MPa, and to correct the situation, a fuel injection start angle retarded by 8 crank angle degrees was used

Summary

Introduction

Conversion of diesel engines for operation on natural gas is important because there are more explored reserves of natural gas than oil on our planet, the price of natural gas is twice lower in Russia and the price difference will grow as the oil reserves are depleted. This requires the use of charging systems ensuring the compressor pressure ratio of 5.5 and higher Reaching such a high pressure ratio in a conventionally compressor results in a drop of efficiency and overheating of the compressor wheel which needs more expensive materials. The compressors have high thermal loads and their wheels are cooled by the charging air from the intercooler after reaching the pressure ratio of about 4.0 Production of these turbochargers requires the use of high-precision manufacturing equipment, advanced materials and technologies. It is possible to get the required pressure ratio of 5.5 and higher in two-stage turbocharging systems using ordinary turbochargers having the pressure ratio of 2.5-3.5 Such turbochargers have been long manufactured in Russia and they have proven high durability in the most different operating. The disadvantages are larger weight and dimensions and longer “turbo-lag” due to a higher inertia of two rotors

Problem Statement

Simulation Model

Results and analysis

Conclusions